Battery Management Circuit, Balancing Circuit, and Device to be Charged

ABSTRACT

A battery management circuit and a battery management method, a balancing circuit and a balancing method, and a device to be charged are provided. The battery management circuit includes a first charging channel, a balancing circuit, and a communication circuit. Through the first charging channel, direct charging is conducted on a battery including a first cell and a second cell coupled in series. The communication circuit is configured to communicate with a power supply device, when the power supply device charges the battery through the first charging channel. The balancing circuit is a balancing circuit based on an RLC series circuit and configured to balance voltage of the first cell and voltage of the second cell.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of International Application No.PCT/CN2017/087829, filed on Jun. 9, 2017, which claims priority toInternational Application No. PCT/CN2016/101944, filed on Oct. 12, 2016and International Application No. PCT/CN2017/073653, filed on Feb. 15,2017, the disclosures of all of which are hereby incorporated byreference in their entireties.

TECHNICAL FIELD

This disclosure relates to the field of charging technology, and moreparticularly to a battery management circuit and a battery managementmethod, a balancing circuit and a balancing method, and a device to becharged.

BACKGROUND

At present, devices to be charged, such as smart phones, are enjoyingincreasing popularity among consumers. However, the device to be chargedneeds to be charged frequently due to its high power consumption.

In order to improve charging speed, a practical scheme is to charge thedevice to be charged with large current. The larger the current, thehigher the charging speed is. Nevertheless, the heating problem of thedevice to be charged is also getting more serious.

Therefore, requirements on reducing heating of the device to be chargedare proposed.

SUMMARY

Implementations of the disclosure provide a battery management circuitand a battery management method, a balancing circuit and a balancingmethod, and a device to be charged, where, on the premise of guaranteedcharging speed, heating of the device to be charged can be reduced.

According to a first aspect of the disclosure, a battery managementcircuit is provided. The battery management circuit includes a firstcharging channel, a balancing circuit, and a communication circuit.Through the first charging channel, charging voltage and/or chargingcurrent are received from a power supply device and applied directly toa battery for charging, where the battery includes a first cell and asecond cell coupled in series. When the power supply device charges thebattery through the first charging channel, the communication circuit isconfigured to communicate with the power supply device to make magnitudeof the charging voltage and/or charging current provided by the powersupply device match a present charging stage of the battery. Thebalancing circuit is coupled with the first cell and the second cell andconfigured to balance voltage of the first cell and voltage of thesecond cell. The balancing circuit includes an RLC series circuit, aswitch circuit, and a control circuit. The switch circuit has one endcoupled with the first cell and the second cell and another end coupledwith the RLC series circuit. The switch circuit has a control endcoupled with the control circuit. The control circuit is configured tocontrol the switch circuit to make the first cell and the second cellalternately form a closed loop with the RLC series circuit to provideinput voltage for the RLC series circuit, when the voltage of the firstcell and the voltage of the second cell are unbalanced.

According to a second aspect of the disclosure, a device to be chargedis provided. The device to be charged includes a battery and the batterymanagement circuit according to the first aspect of the disclosure,where the battery includes a first cell and a second cell coupled inseries.

According to a third aspect of the disclosure, a balancing circuit isprovided. The balancing circuit includes an RLC series circuit, a switchcircuit, and a control circuit. The switch circuit has one end coupledwith a first cell and a second cell and another end coupled with the RLCseries circuit, and the switch circuit has a control end coupled withthe control circuit. The control circuit is configured to control theswitch circuit to make the first cell and the second cell alternatelyform a closed loop with the RLC series circuit to provide input voltagefor the RLC series circuit, when the voltage of the first cell and thevoltage of the second cell are unbalanced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram illustrating a charging systemaccording to an implementation of the present disclosure.

FIG. 2 is a schematic diagram illustrating a coupling relationshipbetween a balancing circuit and cells according to an implementation ofthe present disclosure.

FIG. 3 is an equivalent circuit diagram illustrating an RLC seriescircuit according to an implementation of the present disclosure.

FIG. 4 is a waveform diagram illustrating input voltage of an RLC seriescircuit according to an implementation of the present disclosure.

FIG. 5 is a diagram illustrating correspondence between an input voltagewaveform of an RLC series circuit and a current waveform of an RLCseries circuit according to an implementation of the present disclosure.

FIG. 6 is an exemplary diagram illustrating an alternativeimplementation of a switch circuit according to an implementation of thepresent disclosure.

FIG. 7 is an exemplary diagram illustrating another alternativeimplementation of a switch circuit according to an implementation of thepresent disclosure.

FIG. 8 is a flowchart illustrating a control method according to animplementation of the present disclosure.

FIG. 9 is a flowchart illustrating a control method according to anotherimplementation of the present disclosure.

FIG. 10 is a schematic structural diagram illustrating a charging systemaccording to another implementation of the present disclosure.

FIG. 11 is a schematic structural diagram illustrating a device to becharged according to an implementation of the present disclosure.

FIG. 12 is a schematic diagram illustrating a waveform of a pulsatingdirect current (DC) current according to an implementation of thepresent disclosure.

FIG. 13 is a flowchart illustrating a quick charging process accordingto an implementation of the present disclosure.

FIG. 14 is a schematic flowchart illustrating a battery managementmethod according to an implementation of the present disclosure.

DETAILED DESCRIPTION

In the following, when we refer to “A and/or B”, it means A alone, Balone, or both A and B. For example, when we refer to “charging currentand/or charging voltage”, it means charging current, charging voltage,or, both charging current and charging voltage.

A power supply device configured to charge a device to be charged hasbeen provided in the related art. The power supply device works in aconstant-voltage mode, where voltage output by the power supply deviceremains nearly constant, such as 5V, 9V, 12V, 20V, etc.

Voltage output by the power supply device is not suitable for beingapplied directly to a battery. Instead, the voltage output by the powersupply device needs to be converted by a conversion circuit of thedevice to be charged, so that expected charging voltage and/or chargingcurrent of the battery of the device to be charged can be acquired.

The conversion circuit is configured to convert voltage output by thepower supply device, so as to meet the requirements on expected chargingvoltage and/or charging current of the battery.

As an implementation, the conversion circuit can be a chargingmanagement module, such as a charging integrated circuit (IC), which,when the battery is charged, is configured to manage the chargingvoltage and/or charging current of the battery. The conversion circuitfunctions as a voltage feedback module and/or a current feedback module,so as to implement management of the charging voltage and/or chargingcurrent of the battery.

For example, a charging process of the battery can include at least oneof a trickle charging stage, a constant-current charging stage, and aconstant-voltage charging stage. In the trickle charging stage, theconversion circuit can utilize a current feedback loop, so as to makecurrent flowing into the battery in the trickle charging stage satisfyexpected charging current of the battery (such as a first chargingcurrent). In the constant-current charging stage, the conversion circuitcan utilize a current feedback loop, so as to make current flowing intothe battery in the constant-current charging stage satisfy expectedcharging current of the battery (such as a second charging current,which may be higher than the first charging current). In theconstant-voltage charging stage, the conversion circuit can utilize avoltage feedback loop, so as to make voltage applied to the battery inthe constant-voltage charging stage satisfy expected charging voltage ofthe battery.

As one implementation, when the voltage output by the power supplydevice is higher than expected charging voltage of the battery, theconversion circuit can be configured to decrease (that is, step down)the voltage output by the power supply device, so as to make decreasedcharging voltage meet requirements on the expected charging voltage ofthe battery. As another implementation, when the voltage output by thepower supply device is lower than the expected charging voltage of thebattery, the conversion circuit can be configured to increase (that is,step up) the voltage output by the power supply device, so as to makeincreased charging voltage meet requirements on the expected chargingvoltage of the battery.

As yet another implementation, the voltage output by the power supplydevice is a constant 5V voltage, for example. When the battery includesa single cell (for example, a lithium battery cell, with a 4.2V chargingcut-off voltage), the conversion circuit (such as a Buck circuit) candecrease the voltage output by the power supply device, so as to makethe decreased charging voltage meet requirements on the expectedcharging voltage of the battery.

As still another implementation, the voltage output by the power supplydevice is a constant 5V voltage, for example. When the power supplydevice charges two or more single-cell batteries coupled in series (forexample, a lithium battery cell, with a 4.2V charging cut-off voltage),the conversion circuit (such as a Boost circuit) can increase thevoltage output by the power supply device, so as to make the increasedcharging voltage meet requirements on the expected charging voltage ofthe battery.

The conversion circuit is limited by low circuit conversion efficiency,which results in electrical energy that fails to be converteddissipating in the form of heat. The heat can be accumulated inside thedevice to be charged. Since designed space and heat dissipation space ofthe device to be charged are both very small, for example, the physicalsize of a user's mobile terminal is increasingly lighter and thinner,and a large number of electronic components are densely arranged in themobile terminal at the same time, difficulty in designing the conversioncircuit is increased. In addition, it is difficult to remove promptlyheat accumulated inside the device to be charged, which in turn resultsin abnormality of the device to be charged.

For example, heat accumulated inside the conversion circuit may causeheat interference with electronic components near the conversioncircuit, which results in working abnormality of the electroniccomponents. For another example, the heat accumulated inside theconversion circuit may shorten service life of the conversion circuitand the electronic components near the conversion circuit. For yetanother example, the heat accumulated inside the conversion circuit maycause heat interference with the battery, which in turn brings aboutabnormality of charge and discharge of the battery. For still anotherexample, the heat accumulated inside the conversion circuit may raisetemperature of the device to be charged and thus influence userexperience in the charging process. For still another example, the heataccumulated inside the conversion circuit may result in short circuit ofthe conversion circuit itself, causing abnormality of charging since thevoltage output by the power supply device is applied directly to thebattery. In case that the battery is charged with overvoltage for a longtime, battery explosion may even occur, thus putting users at risk.

According to an implementation of the present disclosure, a power supplydevice with adjustable output voltage is provided. The power supplydevice can acquire state information of a battery. The state informationof a battery can include present power and/or present voltage of thebattery. The power supply device can adjust output voltage of the powersupply device itself according to the state information of the batteryacquired, so as to meet requirements on expected charging voltage and/orcharging current of the battery. Output voltage adjusted by the powersupply device can be applied directly to the battery to charge thebattery (referred to as “direct charging” hereinafter). In addition, inthe constant-current charging stage of the battery, the output voltageadjusted by the power supply device can be applied directly to thebattery for charging.

The power supply device can function as a voltage feedback module and/ora current feedback module, so as to achieve management of the chargingvoltage and/or charging current of the battery.

The power supply device configured to adjust the output voltage of thepower supply device itself according to the state information of thebattery acquired can be configured to acquire the state information ofthe battery in real time and adjust the output voltage of the powersupply device itself according to real-time state information of thebattery acquired each time, so as to meet requirements on the expectedcharging voltage and/or charging current of the battery.

The power supply device configured to adjust the output voltage of thepower supply device itself according to the real-time state informationof the battery acquired can be configured to acquire, with increase involtage of the battery in the charging process, current stateinformation of the battery at different time points in the chargingprocess and adjust in real time the output voltage of the power supplydevice itself according to the current state information of the battery,so as to meet requirements on the expected charging voltage and/orcharging current of the battery.

For example, the charging process of the battery can include at leastone of the trickle charging stage, the constant-current charging stage,and the constant-voltage charging stage. In the trickle charging stage,the power supply device can output the first charging current in thetricked charging stage to charge the battery, so as to meet requirementson expected charging current (the first charging current can be aconstant DC current) of the battery. In the constant-current chargingstage, the power supply device can utilize the current feedback loop tomake the current output in the constant-current charging stage from thepower supply device to the battery meet requirements of the battery onexpected charging current, such as the second charging current. Thesecond charging current may be a pulsating waveform current and may belarger than the first charging current, where a peak value (that is,peak current) of the pulsating waveform current in the constant-currentcharging stage may be greater than magnitude of the constant DC currentin the trickle charging stage, and “constant-current” in theconstant-current charging stage may refer to a situation where peakvalue or average value of the pulsating waveform current remain nearlyconstant. In the constant-voltage charging stage, the power supplydevice can utilize the voltage feedback loop to make the voltage outputin the constant-voltage charging stage from the power supply device tothe device to be charged (that is, constant DC voltage) remain constant.

For example, in implementations of the present disclosure, the powersupply device can be mainly configured to control the constant-currentcharging stage of the battery of the device to be charged. In otherimplementations, control of the trickle charging stage and theconstant-voltage charging stage of the battery of the device to becharged can also be cooperatively completed by the power supply deviceof the implementation of the present disclosure and an extra chargingchip of the device to be charged. Compared with charging power of thebattery received in the constant-current charging stage, charging powersof the battery received in the trickle charging stage and in theconstant-voltage charging stage are lower, so conversion efficiency lossand heat accumulation of the charging chip of the device to be chargedare acceptable. It should be noted that, in implementations of thepresent disclosure, the constant-current charging stage or theconstant-current stage can refer to a charging mode of controllingoutput current of the power supply device but does not require that theoutput current of the power supply device remain completely constant,and may be, for example, a peak value or an average value of a pulsatingwaveform current output by the power supply device remaining nearlyconstant, or remaining nearly constant within a certain time period.Practically, for example, in the constant-current charging stage, thepower supply device usually charges the battery in a multi-stageconstant current charging manner.

Multi-stage constant current charging can include N constant-currentstages, where N is an integer not less than two. In the multi-stageconstant current charging, a first stage charging begins with apre-determined charging current. The N constant-current stages of themulti-stage constant current charging are executed in sequence from thefirst stage to an N^(th) stage. When a previous constant-current stageends and a next constant-current stage begins, the peak value or averagevalue of the pulsating waveform may decrease. When voltage of thebattery reaches a threshold value of charging cut-off voltage, theprevious constant-current stage ends and the next constant-current stagebegins. A current conversion process between two adjacentconstant-current stages may be a gradual process or in a step-likemanner.

In addition, in case that the current output by the power supply deviceis a pulsating DC current, the constant-current mode can refer to acharging mode of controlling a peak value or an average value of thepulsating DC current, that is, controlling the peak value of the currentoutput by the power supply device not greater than current correspondingto the constant-current mode. Furthermore, in case that the currentoutput by the power supply device is an alternating current (AC)current, the constant-current mode can refer to a charging mode ofcontrolling a peak value of the AC current.

In addition, it should be noted that, in the implementations of thepresent disclosure, the device to be charged can be a terminal. The“terminal” can include but is not limited to a device configured via awired line and/or a wireless interface to receive/transmit communicationsignals. Examples of the wired line may include, but are not limited to,at least one of a public switched telephone network (PSTN), a digitalsubscriber line (DSL), a digital cable, a direct connection cable,and/or other data connection lines or network connection lines. Examplesof the wireless interface may include, but are not limited to, awireless interface with a cellular network, a wireless local areanetwork (WLAN), a digital television network (such as a digital videobroadcasting-handheld (DVB-H) network), a satellite network, an AM-FMbroadcast transmitter, and/or with other communication terminals. Acommunication terminal configured to communicate via a wirelessinterface may be called a “wireless communication terminal”, a “wirelessterminal”, and/or a “mobile terminal”. Examples of a mobile terminal mayinclude, but are not limited to, a satellite or cellular telephone, apersonal communication system (PCS) terminal capable of cellular radiotelephone, data processing, fax, and/or data communication, a personaldigital assistant (PDA) equipped with radio telephone, pager,Internet/Intranet access, web browsing, notebook, calendar, and/orglobal positioning system (GPS) receiver, and/or other electronicdevices equipped with radio telephone capability such as a conventionallaptop or a handheld receiver. In addition, in the implementations ofthe present disclosure, the device to be charged or terminal can alsoinclude a power bank. The power bank can be charged by the power supplydevice and thus store the energy to charge other electronic devices.

In addition, in the implementations of the present disclosure, when apulsating waveform voltage output by the power supply device is applieddirectly to a battery of the device to be charged to charge the battery,charging current can be represented in the form of a pulsating wave(such as a steamed bun wave). It can be understood that, the chargingcurrent can charge the battery in an intermittent manner. Period of thecharging current can vary with frequency of an input AC such as an ACpower grid. For instance, frequency corresponding to the period of thecharging current is N times (N is a positive integer) or N times thereciprocal of frequency of a power grid. Additionally, when the chargingcurrent charges the battery in an intermittent manner, current waveformcorresponding to the charging current can include one pulsation or onegroup of pulsations synchronized with the power grid.

As an implementation, in the implementations of the present disclosure,when the battery is charged (such as in at least one of the tricklecharging stage, the constant-current charging stage, and theconstant-voltage charging stage), the battery can receive a pulsating DC(direction remains constant, and magnitude varies with time), an AC(both direction and magnitude vary with time), or a DC (that is, aconstant DC, neither magnitude nor direction varies with time) output bythe power supply device.

As to a conventional device to be charged, the device to be chargedusually has only one single cell. When the single cell is charged withlarge charging current, heating of the device to be charged is serious.In order to guarantee charging speed and reduce heating of the device tobe charged, structure of the cell of the device to be charged ismodified in the implementation of the present disclosure. A battery withcells coupled in series, together with a battery management circuit thatis able to conduct direct charging on the battery with cells coupled inseries, is provided. Since, to achieve equal charging speed, chargingcurrent of the battery with cells coupled in series is 1/N time themagnitude of charging current of the battery with one single cell, whereN represents the number of cells coupled in series of the device to becharged. For the equal charging speed, the battery management circuit ofthe implementation of the present disclosure acquires smaller chargingcurrent from an external power supply device, thereby reducing heatingin the charging process. The following will describe the implementationof the disclosure in detail in conjunction with FIG. 1.

FIG. 1 is a schematic structural diagram illustrating a charging systemaccording to an implementation of the present disclosure. The chargingsystem includes a power supply device 10, a battery management circuit20, and a battery 30. The battery management circuit 20 can beconfigured to manage the battery 30. As an implementation, the batterymanagement circuit 20 can be configured to manage a charging process ofthe battery 30, such as selecting a charging channel, controllingcharging voltage and/or charging current, and so on. As anotherimplementation, the battery management circuit 20 can be configured tomanage cells of the battery 30, such as balancing voltage between thecells of the battery 30.

The battery management circuit 20 can include a first charging channel21 and a communication circuit 23.

Through the first charging channel 21, charging voltage and/or chargingcurrent can be received from the power supply device 10 and applied tothe battery 30 for charging.

In other words, through the first charging channel 21, direct chargingcan be conducted on the battery 30 by applying directly the chargingvoltage and/or charging current received from the power supply device 10to the battery 30. “Direct charging” is elaborated in the wholedisclosure and will not be repeated herein. The first charging channel21 can be referred to as a direct charging channel. The direst chargingchannel does not need to be provided with a conversion circuit such as acharging IC. That is to say, unlike a conventional charging channel,through the direct charging channel, the charging voltage and/orcharging current received from the power supply device do not need to beconverted and then applied to the battery. Instead, through the directcharging channel, the charging voltage and/or charging current receivedfrom the power supply device can be applied directly to the battery.

The first charging channel 21 can be, for example, a wire. Optionally,the first charging channel 21 can be provided with other circuitcomponents unrelated to charging voltage and/or charging currentconversion. For instance, the battery management circuit 20 includes thefirst charging channel 21 and a second charging channel. The firstcharging channel 21 can be provided with a switch component configuredto switch between charging channels, which will be described in detailin FIG. 10.

The power supply device 10 can be the power supply device withadjustable output voltage mentioned above. However, the types of thepower supply device 10 are not limited herein. For example, the powersupply device 10 can be a device specially configured to charge such asan adaptor, a power bank, etc., or other devices that are able toprovide both power and data service such as a computer.

The battery 30 according the implementations of the present disclosurecan include multiple cells coupled in series (at least two cells). Thecells coupled in series can be configured to divide the charging voltageprovided by the power supply device 10 in the charging process. Asillustrated in FIG. 1, a first cell 31 a and a second cell 31 b can beany two of the multiple cells or any two groups of the multiple cells.Exemplarily, when the first cell 31 a (or the second cell 31 b) includesa group of cells, all cells in this cell-group can be coupled in seriesor in parallel. The coupling manners of the cells are not limitedherein.

The battery 30 can be one battery or multiple batteries. That is to say,the cells coupled in series according to the implementations of thepresent disclosure can be packaged into one battery pack to form onebattery or be packaged into multiple battery packs to form multiplebatteries. For instance, the battery 30 can be one battery. The onebattery includes the first cell 31 a and the second cell 31 b coupled inseries. For another instance, the battery 30 can include two batteries.One of the two batteries includes the first cell 31 a, and the other oneof the two batteries includes the second cell 31 b.

When the power supply device 10 charges the battery 30 through the firstcharging channel 21, the communication circuit 23 can be configured tocommunicate with the power supply device 10, so as to make magnitude ofthe charging voltage and/or charging current received from the powersupply device 10 match a present charging stage of the battery 30, ormake magnitude of the charging voltage and/or charging current receivedfrom the power supply device 10 meet requirements on the chargingvoltage and/or charging current in the present charging stage of thebattery 30.

As mentioned above, the first charging channel 21 is a direct chargingchannel, through which the charging voltage and/or charging currentreceived from the power supply device 10 can be applied directly to thebattery 30. In order to achieve direct charging, the implementations ofthe present disclosure introduce in the battery management circuit 20 acontrol circuit with a communication function, that is, thecommunication circuit 23. The communication circuit 23 can be configuredto keep communicating with the power supply device 10 in a directcharging process to form a closed-loop feedback mechanism, so as toenable the power supply device 10 to acquire the state information ofthe battery in real time, thus adjusting continuously the chargingvoltage and/or charging current flowing into the first charging channelto guarantee that magnitude of the charging voltage and/or chargingcurrent received from the power supply device 10 matches the presentcharging stage of the battery 30.

The present charging stage of the battery 30 can be any one of thetrickle charging stage, the constant-current charging stage, and theconstant-voltage charging stage.

In the trickle charging stage of the battery 30, the communicationcircuit 23 can be configured to communicate with the power supply device10, so that the power supply device 10 can adjust charging currentprovided for the first charging channel 21, to make the charging currentmatch charging current corresponding to the trickle charging stage, ormake the charging current to meet requirements on charging current inthe trickle charging stage of the battery 30.

In the constant-voltage charging stage of the battery 30, thecommunication circuit 23 can be configured to communicate with the powersupply device 10, so that the power supply device 10 can adjust chargingvoltage provided for the first charging channel 21, to make the chargingvoltage match charging voltage corresponding to the constant-voltagecharging stage, or make the charging voltage meet requirements oncharging voltage in the constant-voltage charging stage of the battery30.

In the constant-current charging stage of the battery 30, thecommunication circuit 23 can be configured to communicate with the powersupply device 10, so that the power supply device 10 can adjust chargingcurrent provided for the first charging channel 21, to make the chargingcurrent match charging current corresponding to the constant-currentcharging stage, or make the charging current meet requirements oncharging current in the constant-current charging stage of the battery30.

In implementations of the present disclosure, content communicated andcommunication methods between the communication circuit 23 and the powersupply device 10 are not limited. The above aspects will be described indetail hereinafter in conjunction with specific implementations and willnot be repeated herein.

The battery management circuit 20 can further include a balancingcircuit 22. The balancing circuit 22 can be coupled with the first cell31 a and the second cell 31 b to balance the voltage of the first cell31 a and the voltage of the second cell 31 b.

The battery management circuit 20 according to the implementations ofthe present disclosure can be configured to conduct direct charging onthe battery. In other words, the battery management circuit 20 accordingto the implementation of the present disclosure is a battery managementcircuit that supports a direct charging architecture. In the directcharging architecture, the direct charging channel does not need to beprovided with a conversion circuit, which in turn reduces heating of thedevice to be charged in the charging process.

Direct charging scheme can reduce heating of the device to be charged inthe charging process to some extent. However, when charging currentreceived from the power supply device 10 is excessive, such as an outputcurrent of the power supply device 10 reaching a magnitude between 5 Aand 10 A, heating of the battery management circuit 20 is still serious,and thus safety problems may occur.

In order to guarantee charging speed and further reduce heating of thedevice to be charged in the charging process, structure of the batteryis modified in the implementations of the present disclosure. A batterywith cells coupled in series is provided. Compared with a battery withone single cell, to achieve an equal charging speed, charging current ofthe battery with cells coupled in series is 1/N time the magnitude ofcharging current of a battery with one single cell, where N representsthe number of cells coupled in series of the device to be charged. Thatis to say, as to an equal charging speed, the implementations of thepresent disclosure can substantially reduce magnitude of chargingcurrent, thereby further reducing heating of the device to be charged inthe charging process.

For example, as to a single-cell battery of 3000 mAh, a charging currentof 9 A (ampere) is needed to reach a charging speed of 3 C (Coulomb). Inorder to reach an equal charging speed and reduce heating of the deviceto be charged in the charging process at the same time, two cells, eachof 1500 mAh, can be coupled in series to replace the single cell of 3000mAh. As a result, only a charging current of 4.5 A is needed to reachthe charging speed of 3 C. In addition, compared with the chargingcurrent of 9 A, the charging current of 4.5 A produces substantiallyless heat than the charging current of 9 A.

In addition, the power management circuit in the implementations of thepresent disclosure can be configured to balance voltage between cellscoupled in series and make parameters of the cells coupled in series beapproximate, so as to facilitate unified management of cells of thebattery. Furthermore, in case that the battery includes multiple cells,keeping parameters between the cells consistent can improve overallperformance and service life of the battery.

It should be noted that, since a direct charging manner is adopted tocharge the battery 30 with multiple cells coupled in series through thefirst charging channel 21, charging voltage received from the powersupply device 10 needs to be higher than total voltage of the battery30. In general, working voltage of a single cell is between 3.0V and4.35V. In case of double cells coupled in series, when the firstcharging channel 21 is adopted in the charging process, output voltageof the power supply device 10 can be set equal to or higher than 10V.

The balancing circuit 22 can be implemented in various manners. Theimplementations of the disclosure provide a balancing circuit based onan RLC series circuit. The following will describe in detail thebalancing circuit based on an RLC series circuit in conjunction withFIG. 2 to FIG. 9.

As illustrated in FIG. 2, the balancing circuit 22 includes an RLCseries circuit 25, a switch circuit 26, and a control circuit 27. Theswitch circuit 26 has one end coupled with the first cell 31 a and thesecond cell 31 b and another end coupled with the RLC series circuit 25.The switch circuit 26 has a control end coupled with the control circuit27.

The control circuit 27 is configured to control the switch circuit 26 tomake the first cell 31 a and the second cell 31 b alternately form aclosed loop with the RLC series circuit 25 to provide input voltage forthe RLC series circuit 25, when the voltage of the first cell 31 a andthe voltage of the second cell 31 b are unbalanced. In other words, thecontrol circuit 27 can be configured to control the switch circuit 26 tomake the first cell 31 a and the second cell 31 b alternately be avoltage source of the RLC series circuit 25 to provide input voltage forthe RLC series circuit 25.

When the control circuit 27 couples alternately the first cell 31 a andthe second cell 31 b with the RLC series circuit 25 via the switchcircuit 26, an equivalent circuit diagram of FIG. 3 can be obtained. Asillustrated in FIG. 3, VG1 represents an equivalent power supply of theRLC series circuit 25 formed by the first cell 31 a and the second cell31 b being alternately coupled with the RLC series circuit 25. Forexample, the voltage of the first cell 31 a is 4.3V and the voltage ofthe second cell 31 b is 4.2V. A voltage waveform of VG1 is illustratedin FIG. 4. The input voltage can be divided into a DC component of a4.25V voltage and an AC component of a 4.25V voltage. V_(pp) of the ACcomponent (difference between a minimum value of the AC component and amaximum value of the AC component) is 0.5V.

Still take the voltage of the first cell 31 a being 4.3V and the voltageof the second cell 31 b being 4.2V as an example. FIG. 5 is a diagramillustrating correspondence between a waveform of Current I in the RLCseries circuit 25 and a voltage waveform of VG1 of the RLC seriescircuit. It should be understood that, the specific value of I dependson overall impedance of the RLC series circuit 25 and is not limitedherein.

When the voltage of VG1 is 4.3V, it means that the first cell 31 a iscoupled with the RLC series circuit 25; when input voltage of VG1 is4.2V it means that the second cell 31 b is coupled with the RLC seriescircuit 25. By comparing the waveform of Current I in the RLC seriescircuit 25 and the voltage waveform of VG1 of the RLC series circuit 25,it can be seen that when the second cell 31 b is coupled with the RLCseries circuit 25, current in the RLC series circuit 25 is a negativecurrent, that is, the current flows from the outside to the second cell31 b to charge the second cell 31 b, so as to balance the voltage of thefirst cell 31 a and the voltage of the second cell 31 b.

The balancing circuit in the implementations of the disclosure is abalancing circuit based on an RLC series circuit. The balancing circuithas a simple circuit structure and is able to reduce complexity of abattery management circuit. In addition, the number of components of theRLC series circuit is small and total impedance of the RLC seriescircuit is low. Therefore, heating is low during working of thebalancing circuit.

As pointed above, when the control circuit 27 couples alternately thefirst cell 31 a and the second cell 31 b with the RLC series circuit 25,the waveform of the current I in the RLC series circuit 25 isillustrated in FIG. 5. When the impedance of the RLC series circuit 25is excessively high, magnitude of the current I is low, and a balancingprocess between the voltage of the first cell 31 a and the voltage ofthe second cell 31 b is slow.

The RLC series circuit 25 has a resonant characteristic. The magnitudeof the current I in the RLC series circuit 25 depends on voltagefrequency of VG1 (that is, the frequency of the input voltage of the RLCseries circuit 25). The more the voltage frequency of VG1 approximatesto resonant frequency of the RLC series circuit 25, the higher thecurrent in the RLC series circuit 25 is.

Therefore, in order to improve efficiency in energy transfer of thebalancing circuit, the control circuit 27 can control the switch circuit26, to make frequency of the input voltage of the RLC series circuit 25approximate to the resonant frequency of the RLC series circuit 25,which can substantially improve efficiency in energy transfer betweenthe first cell 31 a and the second cell 31 b. When the frequency of theinput voltage of the RLC series circuit 25 reaches the resonantfrequency of the RLC series circuit 25, that is, the frequency of theinput voltage of the RLC series circuit 25 reaches f=1/π√{square rootover (LC)}, where L represents self-inductance coefficient of Inductor Land C represents capacitance of Capacitor C, the RLC series circuit 25goes into a resonant state. When the RLC series circuit 25 is in aresonant state, Inductor L and Capacitor C have voltages which are equalin magnitude and opposite in phase, and thus the voltages can canceleach other out, which makes Inductor L and Capacitor C form a shortcircuit (Inductor L and Capacitor C are equivalent to a wire). The RLCseries circuit 25 becomes a pure resistance circuit, magnitude of thecurrent I in the RLC series circuit 25 reaches a maximum value, andefficiency in energy transfer in the balancing circuit 22 reaches thehighest level.

The configuration of the switch circuit 26 is not limited herein, aslong as the first cell 31 a and the second cell 31 b can be alternatelycoupled with the RLC series circuit 25 through on-off of a switchcomponent(s) of the switch circuit 26. The following will provideseveral alternative implementations of the switch circuit 26.

FIG. 6 illustrates an alternative implementation of the switch circuit.As illustrated in FIG. 6, the switch circuit includes a first switchtransistor Q1, a second switch transistor Q2, a third switch transistorQ3, and a fourth switch transistor Q4. The first switch transistor Q1has a first connected end 60 coupled with a positive electrode of thefirst cell 31 a and a second connected end 61 coupled with a firstconnected end 63 of the second switch transistor Q2. The second switchtransistor Q2 has a second connected end 64 coupled with a firstconnected end 66 of the third switch transistor Q3 and a negativeelectrode of the first cell 31 a. The third switch transistor Q3 has asecond connected end 67 coupled with a first connected end 69 of thefourth switch transistor Q4. The fourth switch transistor Q4 has asecond connected end 70 coupled with a negative electrode of the secondcell 31 b. The second cell 31 b has a positive electrode coupled with anegative electrode of the first cell 31 a. The first switch transistorQ1 has a control end 62 coupled with the control circuit 27. The secondswitch transistor Q2 has a control end 65 coupled with the controlcircuit 27. The third switch transistor Q3 has a control end 68 coupledwith the control circuit 27. The fourth switch transistor Q4 has acontrol end 71 coupled with the control circuit 27. Components of theRLC series circuit (including a capacitor C, an inductor L, and aresistor R illustrated in FIG. 6) are coupled in series between thesecond connected end 61 of the first switch transistor Q1 and the secondconnected end 67 of the third switch transistor Q3.

FIG. 7 illustrates another alternative implementation of the switchcircuit. As illustrated in FIG. 7, the switch circuit includes a firstswitch transistor Q1, a second switch transistor Q2, a third switchtransistor Q3, and a fourth switch transistor Q4. The first switchtransistor Q1 has a first connected end 60 coupled with a positiveelectrode of the first cell 31 a and a second connected end 61 coupledwith a first connected end 63 of the second switch transistor Q2. Thesecond switch transistor Q2 has a second connected end 64 coupled with afirst connected end 66 of the third switch transistor Q3. The thirdswitch transistor Q3 has a second connected end 67 coupled with a firstconnected end 69 of the fourth switch transistor Q4. The fourth switchtransistor Q4 has a second connected end 70 coupled with a negativeelectrode of the second cell 31 b. The second cell 31 b has a positiveelectrode coupled with a negative electrode of the first cell 31 a. Thefirst switch transistor Q1 has a control end 62 coupled with the controlcircuit 27. The second switch transistor Q2 has a control end 65 coupledwith the control circuit 27. The third switch transistor Q3 has acontrol end 68 coupled with the control circuit 27. The fourth switchtransistor Q4 has a control end 71 coupled with the control circuit 27.At least part of components of the RLC series circuit are coupled inseries between the second connected end 64 of the second switchtransistor Q2 and the negative electrode of the first cell 31 a, andcomponents of the RLC series circuit, other than the above mentioned atleast part of components of the RLC series circuit coupled in seriesbetween the second connected end 64 of the second switch transistor Q2and the negative electrode of the first cell 31 a, are coupled in seriesbetween the second connected end 61 of the first switch transistor Q1and the second connected end 67 of the third switch transistor Q3.

The at least part of components of the RLC series circuit mentionedabove can be at least one of Capacitor C, Inductor L, and Resistor R.For instance, the at least part of components of the RLC series circuitmentioned above can be Inductor L, and the components other than the atleast part of components of the RLC series circuit, can be Capacitor Cand Resistor R. For another instance, the at least part of components ofthe RLC series circuit mentioned above can be Inductor L and CapacitorC, and the components of the RLC series circuit, other than the at leastpart of components of the RLC series circuit, can be Resistor R. For yetanother instance, the at least part of components of the RLC seriescircuit mentioned above can be Resistor R, Capacitor C, and Inductor L,and there is no other component except the at least part of componentsof the RLC series circuit. In this case, the second connected end 61 ofthe first switch transistor Q1 can be coupled with the second connectedend 67 of the third switch transistor Q3 directly through wires.

The switch transistor mentioned above can be, for example, a MOS (metaloxide semiconductor) transistor. In addition, the connected end of theswitch transistor mentioned above can be a source electrode and/or adrain electrode of the switch transistor. The control end of the switchtransistor can be a grid electrode of the switch transistor.

Based on the balancing circuit illustrated in FIG. 6 and FIG. 7, thefollowing will describe alternative control manners of the controlcircuit 27.

FIG. 8 is a flowchart illustrating a control method according to animplementation of the present disclosure. FIG. 8 describes a situationwhere the voltage of the first cell 31 a and the voltage of the secondcell 31 b are unbalanced and the voltage of the first cell 31 a ishigher than the voltage of the second cell 31 b. The control methodillustrated in FIG. 8 includes operations at block 810 to block 840. Thefollowing will describe the method in detail.

At block 810, control the first switch transistor Q1 and the thirdswitch transistor Q3 to an on-state from time t0 to time t1 and controlthe second switch transistor Q2 and the fourth switch transistor Q4 toan off-state from time t0 to time t1, where time t0 represents a starttime of a work period of the control circuit 27 (that is, time 0 of thework period).

It can be seen from FIG. 6 or FIG. 7 that, when the first switchtransistor Q1 and the third switch transistor Q3 are in the on-state andthe second switch transistor Q2 and the fourth switch transistor Q4 arein the off-state, the first cell 31 a, the capacitor C, the inductor L,and the resistor R form a closed circuit, and the first cell 31 aprovides input voltage for the RLC series circuit.

At block 820, control the first switch transistor Q1, the second switchtransistor Q2, the third switch transistor Q3, and the fourth switchtransistor Q4 to the off-state from time t1 to time t2, where a timeperiod from time t1 to time t2 represents a preset first dead time.

A dead time can be understood as a protection time, which aims to avoidthe first switch transistor Q1 and the third switch transistor Q3 beingsimultaneously in the on-state with the second switch transistor Q2 andthe fourth switch transistor Q4 and thus resulting in circuit fault.

At block 830, control the second switch transistor Q2 and the fourthswitch transistor Q4 to the on-state from time t2 to time t3 and controlthe first switch transistor Q1 and the third switch transistor Q3 to theoff-state from time t2 to time t3.

It can be seen from FIG. 6 or FIG. 7 that, when the second switchtransistor Q2 and the fourth switch transistor Q4 are in the on-stateand the first switch transistor Q1 and the third switch transistor Q3are in the off-state, the second cell 31 b, Capacitor C, Inductor L, andResistor R form a closed circuit, and the second cell 31 b providesinput voltage for the RLC series circuit.

In some implementations, value of t3-t2 can be equal to value of t1-t0,that is, a time period of the second switch transistor Q2 and the fourthswitch transistor Q4 being in the on-state can be equal to a time periodof the first switch transistor Q1 and the third switch transistor Q3being in the on-state.

At block 840, control the first switch transistor Q1, the second switchtransistor Q2, the third switch transistor Q3, and the fourth switchtransistor Q4 to the off-state from time t3 to time t4, where t4represents an end time of the work period and a time period from time t3to time t4 represents a preset second dead time.

In some implementations, the second dead time can be equal to the firstdead time.

In addition, in some implementations, by setting reasonably value oft1-t4, work frequency of the control circuit 27 can be made to be equalto the resonant frequency of the RLC series circuit, which can makefrequency of the input voltage of the RLC series circuit be equal to theresonant frequency of the RLC series circuit, thereby prompting the RLCseries circuit to reach the resonant state.

It should be understood that, FIG. 8 illustrates a control time sequenceof the control circuit 27 in any work period. Control time sequences ofother work periods are similar and will not be repeated herein.

FIG. 9 is a flowchart illustrating a control method according to anotherimplementation of the present disclosure. FIG. 9 describes a situationwhere the voltage of the first cell 31 a and the voltage of the secondcell 31 b are unbalanced and the voltage of the second cell 31 b ishigher than the voltage of the first cell 31 a. The control method ofFIG. 9 is similar to that of FIG. 8, and the difference lies in that inFIG. 9, the on and off order of the first switch transistor Q1 and thethird switch transistor Q3 are exchanged with that of the second switchtransistor Q2 and the fourth switch transistor Q4. The control methodillustrated in FIG. 9 includes operations at block 910 to block 940. Thefollowing will describe the method in detail.

At block 910, control the second switch transistor Q2 and the fourthswitch transistor Q4 to an on-state from time t0 to time t1 and controlthe first switch transistor Q1 and the third switch transistor Q3 to anoff-state from time t0 to time t1, where time t0 represents a start timeof a work period of the control circuit 27.

It can be seen from FIG. 6 or FIG. 7 that, when the second switchtransistor Q2 and the fourth switch transistor Q4 are in the on-stateand the first switch transistor Q1 and the third switch transistor Q3are in the off-state, the second cell 31 b, the capacitor C, theinductor L, and the resistor R form a closed circuit, and the secondcell 31 b provides input voltage for the RLC series circuit.

At block 920, control the first switch transistor Q1, the second switchtransistor Q2, the third switch transistor Q3, and the fourth switchtransistor Q4 to the off-state from time t1 to time t2, where a timeperiod from time t1 to time t2 represents a preset first dead time.

At block 930, control the first switch transistor Q1 and the thirdswitch transistor Q3 to the on-state from time t2 to time t3 and controlthe second switch transistor Q2 and the fourth switch transistor Q4 tothe off-state from time t2 to time t3.

It can be seen from to FIG. 6 or FIG. 7 that, when the first switchtransistor Q1 and the third switch transistor Q3 are in the on-state andthe second switch transistor Q2 and the fourth switch transistor Q4 arein the off-state, the first cell 31 a, Capacitor C, Inductor L, andResistor R form a closed circuit, and the first cell 31 a provides inputvoltage for the RLC series circuit.

In some implementations, value of t3-t2 can be equal to value of t1-t0,that is, a time period of the second switch transistor Q2 and the fourthswitch transistor Q4 being in the on-state can be equal to a time periodof the first switch transistor Q1 and the third switch transistor Q3being in the on-state.

At block 940, control the first switch transistor Q1, the second switchtransistor Q2, the third switch transistor Q3, and the fourth switchtransistor Q4 to the off-state from time t3 to time t4, where t4represents an end time of the work period and a time period from time t3to time t4 represents a preset second dead time.

In some implementations, the second dead time can be equal to the firstdead time.

In addition, in some implementations, by setting reasonably value oft1-t4, work frequency of the control circuit 27 can be made to be equalto the resonant frequency of the RLC series circuit, which can makefrequency of the input voltage of the RLC series circuit be equal to theresonant frequency of the RLC series circuit, thereby prompting the RLCseries circuit to reach the resonant state.

It should be understood that, FIG. 9 illustrates a control time sequenceof the control circuit 27 in any work period. Control time sequences ofother work periods are similar and will not be repeated herein.

Optionally, in some implementations, as illustrated in FIG. 10, thebattery management circuit 20 can further include a second chargingchannel 24. The second charging channel 24 is provided with a boostcircuit 25. When the power supply device 10 charges the battery 30through the second charging channel 24, the boost circuit 25 isconfigured to receive initial voltage from the power supply device 10and increase the initial voltage to a target voltage to charge thebattery 30 according to the target voltage. The initial voltage is lowerthan total voltage of the battery 30 and the target voltage is higherthan the total voltage of the battery 30. In addition, as illustrated inFIG. 10, in some implementations, the battery management circuit 20 canfurther include a second control circuit 28. The second control circuit28 can be configured to control switching between the first chargingchannel 21 and the second charging channel 24.

It can be understood from above that, through the first charging channel21, direct charging is conducted on cells of the battery 30, and directcharging requires that charging voltage received from the power supplydevice 10 be higher than total voltage of cells coupled in series of thebattery. For example, as to two cells coupled in series, suppose presentvoltage of each cell is 4V, when the two cells are charged through thefirst charging channel 21, the charging voltage received from the powersupply device 10 is required to be at least higher than 8V. However,output voltage of a conventional power supply device is usually unableto reach 8V (for example, a conventional adaptor usually provides anoutput voltage of 5V), which results in the conventional power supplydevice being unable to charge the battery 30 through the first chargingchannel 21. In order to make the above direct charging circuit becompatible with the conventional power supply device, such as aconventional power adaptor, the second charging channel 24 is providedherein. The second charging channel 24 is provided with a boost circuit25, and the boost circuit 25 is configured to increase the initialvoltage provided by the power supply device 10 to a target voltage tomake the target voltage be higher than the total voltage of the battery30, so as to solve the problem of the conventional power supply devicebeing unable to charge the battery 30 with multiple cells coupled inseries according to the implementations of the disclosure.

The configuration of the boost circuit 25 is not limited herein. Forinstance, a Boost circuit or a charge pump can be adopted to increasevoltage. Optionally, in some implementations, the second chargingchannel 24 can adopt a conventional charging channel design, that is,the second charging channel 24 can be provided with a conversioncircuit, such as a charging IC. The conversion circuit can takeconstant-voltage and constant-current control of the charging process ofthe battery 30 and adjust (such as boost or buck) the initial voltagereceived from the power supply device 10 according to actual needs. Inthe implementations of the disclosure, the initial voltage received fromthe power supply device 10 can be increased to the target voltage byutilizing a boost function of the conversion circuit.

The communication circuit 23 can achieve switching between the firstcharging channel 21 and the second charging channel 24 through a switchcomponent. Specifically, as illustrated in FIG. 10, the first chargingchannel 21 is provided with a switch transistor Q5. When thecommunication circuit 23 controls the switch transistor Q5 to switch-on,the first charging channel 21 works and direct charging is conducted onthe battery 30 through the first charging channel 21. When thecommunication circuit 23 controls the switch transistor Q5 toswitch-off, the second charging channel 24 works and charging isconducted on the battery 30 through the second charging channel 24.

In implementations of the disclosure, a device to be charged isprovided. As illustrated in FIG. 11, the device to be charged 40 caninclude the battery management circuit 20 and the battery 30 describedabove.

At present, a single-cell power supply scheme is generally adopted forcharging in a device to be charged (such as a terminal). Multiple cellscoupled in series are proposed in implementations of the disclosure.Total voltage of the multiple cells is high and is therefore unsuitableto be used directly to supply power to the device to be charged. Inorder to solve this problem, a practical scheme is to adjust workingvoltage of the system of the device to be charged, so as to enable thesystem of the device to be charged to support power supply of multiplecells at the same time. However, this scheme results in too manymodifications to the device to be charged and high cost.

Optionally, in some implementations, the device to be charged 40 can beprovided with a buck circuit, so as to make decreased voltage meetrequirements of the device to be charged 40 on power supply voltage.

For example, working voltage of a single cell is 3.0V to 4.35V. In orderto guarantee normal power supply voltage of the system of the device tobe charged, the buck circuit can be configured to decrease the totalvoltage of the battery 30 to a value between 3.0V and 4.35V. The buckcircuit can be implemented in various manners, such as a Buck circuit, acharge pump, etc., to decrease voltage.

Optionally, in other implementations, a power supply circuit of thedevice to be charged 40 has an input end that can be coupled with bothends of any one single cell of the battery 30. The power supply circuitcan supply power to the system of the device to be charged 40 accordingto voltage of the one single cell.

It should be understood that, voltage decreased by the buck circuit mayhave ripples and in turn influence power supply quality of the device tobe charged. The implementations of the disclosure still adopt one singlecell to supply power to the system of the device to be charged, due tosteady voltage output by one single cell. Therefore, in theimplementations of the disclosure, while a problem of how to supplypower based on a multiple-cell scheme is solved, power supply quality ofthe system of the device to be charged can be guaranteed.

When one single cell is adopted to supply power, imbalance of voltagebetween different cells of the battery 30 may occur. The imbalance ofvoltage between different cells can cause difficulty in batterymanagement. In addition, difference in parameters of cells of thebattery can result in decrease in service life of the battery. In theimplementation of the disclosure, the balancing circuit 22 is used tobalance voltage between cells, thereby keeping voltage between the cellsof the battery 30 balanced even if the above single-cell power supplyscheme is adopted.

With output power of the power supply device increasing, when the powersupply device charges the cells of the device to be charged, lithiumprecipitation may occur, which deceases service life of the cells.

In order to improve reliability and safety of the cells, in someimplementations, the power supply device 10 can be controlled to outputa pulsating DC current (also referred to as a one-way pulsating outputcurrent, a pulsating waveform current, or a steamed bun-wave current).Since the direct charging manner is adopted to charge the battery 30through the first charging channel 21, the pulsating DC current receivedfrom the power supply device 10 can be applied directly to the battery30. As illustrated in FIG. 12, magnitude of the pulsating DC currentvaries periodically. Compared with a constant DC current, the pulsatingDC current can reduce lithium precipitation of a cell, therebyincreasing service life of the cell. In addition, compared with theconstant DC current, the pulsating DC current can decrease possibilityand intensity in arcing of a contact of a charging interface, therebyincreasing service life of the charging interface.

Adjusting charging current output by the power supply device 10 to thepulsating DC current can be achieved in various manners. For example, aprimary filtering circuit and a secondary filtering circuit of the powersupply device 10 can be removed, so as to make the power supply device10 output the pulsating DC current.

Optionally, in some implementations, the charging current received fromthe power supply device 10 by the first charging channel 21 can be an ACcurrent, for example, a primary filtering circuit, a secondaryrectifying circuit, and a secondary filtering circuit of the powersupply device 10 can be removed to make the power supply device 10output the AC current. The AC current can also reduce lithiumprecipitation of the cell and increase the service life of the cell.

Optionally, in some implementations, the power supply device 10 isselectively operable in a first charging mode or a second charging mode.Charging speed of the power supply device 10 charging the battery 30 inthe second charging mode is faster than that of the power supply device10 charging the battery 30 in the first charging mode. In other words,compared with the power supply device 10 working in the first chargingmode, the power supply device 10 working in the second charging modetakes less time to charge battery of the same capacity. In addition, insome implementations, in the first charging mode, the power supplydevice 10 charges the battery 30 through the second charging channel 24;in the second charging mode, the power supply device 10 charges thebattery 30 through the first charging channel 21.

The first charging mode can be a normal charging mode. The secondcharging mode can be a quick charging mode. In the normal charging mode,the power supply device outputs smaller current (usually smaller than2.5 A) or adopts low power (usually lower than 15 W) to charge thebattery of the device to be charged. In the normal charging mode,charging fully a battery of high capacity (such as a 3000 mA battery)usually takes several hours. However, in the quick charging mode, thepower supply device can output larger current (usually larger than 2.5A, such as 4.5 A, 5 A, or even larger) or adopt higher power (usuallyhigher than or equal to 15 W) to charge the battery of the device to becharged. Compared with the normal charging mode, in the quick chargingmode, the power supply device can charge fully the battery of the samecapacity within a substantially shorter charging period and at a highercharging speed.

In addition, the communication circuit 23 can be configured to conducttwo-way communication with the power supply device 10, to control outputof the power supply device 10 in the second charging mode, that is, tocontrol the charging voltage and/or charging current provided by thepower supply device 10 in the second charging mode. The device to becharged 40 can include a charging interface. The communication circuit23 is configured to communicate with the power supply device 10 througha data line of the charging interface. For instance, the charginginterface can be a USB interface. The data line can be a D+ line and/ora D− line of the USB interface. Optionally, the device to be charged 40can be further configured to conduct wireless communication with thepower supply device 10.

Content communicated between the power supply device 10 and thecommunication circuit 23 and control manners of the communicationcircuit 23 on output of the power supply device 10 in the secondcharging mode are not limited herein. For example, the communicationcircuit 23 can be configured to communicate with the power supply device10, interact with present total voltage and/or present power of thebattery 30 of the device to be charged 40, and adjust output voltageand/or output current of the power supply device 10 according to thepresent total voltage and/or present power of the battery 30. Thefollowing will describe in detail the content communicated between thecommunication circuit 23 and the power supply device 10 and the controlmanners of the communication circuit 23 on output of the power supplydevice 10 in the second charging mode in conjunction with specificimplementations of the disclosure.

Description above does not limit master-slave relationship between thepower supply device 10 and the device to be charged (or thecommunication circuit 23 of the device to be charged). That is to say,any one of the power supply device 10 and the device to be charged canfunction as a master device to initiate a two-way communication, andcorrespondingly the other one of the power supply device 10 and thedevice to be charged can function as a slave device to make a firstresponse or a first reply to the communication initiated by the masterdevice. As a practical manner, identities of the master device and theslave device can be determined by comparing levels of the power supplydevice 10 and the device to be charged with reference to earth in acommunication process.

The implementation of the two-way communication between the power supplydevice 10 and the device to be charged is not limited herein. In otherwords, any one of the power supply device 10 and the device to becharged can function as the master device to initiate the communication,and correspondingly the other one of the power supply device 10 and thedevice to be charged can function as the slave device to make the firstresponse or the first reply to the communication initiated by the masterdevice. Besides, the master device can make a second response to thefirst response or the first reply of the slave device, as such, themaster device and the slave device complete a negotiation on chargingmodes. As a possible implementation, charging between the master deviceand the slave device can be executed after completion of multiplenegotiations on charging modes between the master device and the slavedevice, so as to guarantee that the charging process is safe andreliable after negotiations.

The master device can make the second response to the first response orthe first reply to the communication of the slave device as follows. Themaster device receives from the slave device the first response or thefirst reply to the communication and makes the second response to thefirst response or the first reply of the slave device. As an example,when the master device receives from the slave device the first responseor the first reply to the communication within a preset time period, themaster device makes the second response to the first response or thefirst reply of the slave device as follows. The master device and theslave device complete a negotiation on charging modes. Charging betweenthe master device and the slave device is executed in the first chargingmode or in the second charging mode according to the negotiation result,that is, the power supply device 10 is operable in the first chargingmode or in the second charging mode to charge the device to be chargedaccording to the negotiation.

The master device can also make the second response to the firstresponse or the first reply to the communication of the slave device asfollows. When the master device fails to receive from the slave devicethe first response or the first reply to the communication within apreset time period, the master device can still make the second responseto the first response or the first reply made by the slave device. As anexample, when the master device fails to receive from the slave devicethe first response or the first reply to the communication within apreset time period, the master device can still make the second responseto the first response or the first reply made by the slave device asfollows: the master device and the slave device complete a negotiationon charging modes. Charging is executed in the first charging modebetween the master device and the slave device, that is, the powersupply device is operable in the first charging mode to charge thedevice to be charged.

Optionally, in some implementations, after the device to be charged, asthe main device, initiates the communication and the power supply device10, as the subordinate device, makes the first response or the firstreply to the communication initiated by the main device, without thedevice to be charged making the second response to the first response orthe first reply of the power supply device 10, it can be regarded as themain device and the subordinate device completing a negotiation oncharging modes, and thus the power supply device 10 can determine tocharge the device to be charged in the first charging mode or in thesecond charging mode according to the negotiation.

Optionally, in some implementations, the communication circuit 23conducts two-way communication with the power supply device 10, so as tocontrol output of the power supply device 10 in the second charging modeas follows. The communication circuit 23 conducts two-way communicationwith the power supply device 10, so as to negotiate charging modesbetween the power supply device 10 and the device to be charged.

Optionally, in some implementations, the communication circuit 23conducts two-way communication with the power supply device 10 tonegotiate charging modes between the power supply device 10 and thedevice to be charged as follows. The communication circuit 23 receives afirst instruction from the power supply device 10, the first instructionis for enquiring whether the device to be charged enable (in otherwords, switches on) the second charging mode; the communication circuit23 sends a reply instruction of the first instruction to the powersupply 10, the reply instruction of the first instruction is forindicating whether the device to be charged agrees to enable the secondcharging mode; in case that the device to be charged agrees to enablethe second charging mode, the communication circuit 23 controls thepower supply device 10 to charge the battery 30 though the firstcharging channel 21.

Optionally, in some implementations, the communication circuit 23conducts two-way communication with the power supply device 10 tocontrol output of the power supply device 10 in the second charging modeas follows. The communication circuit 23 conducts two-way communicationwith the power supply device 10, so as to determine charging voltagewhich is output by the power supply device in the second charging modeand used for charging the device to be charged.

Optionally, in some implementations, the communication circuit 23conducts two-way communication with the power supply device 10, so as todetermine charging voltage which is output by the power supply device inthe second charging mode and used for charging the device to be chargedas follows. The communication circuit 23 receives a second instructionfrom the power supply device 10, the second instruction is for enquiringwhether the charging voltage output by the power supply device 10matches present total voltage of the battery 30 of the device to becharged; the communication circuit 23 sends a reply instruction of thesecond instruction to the power supply 10, the reply instruction of thesecond instruction is for indicating that the voltage output by thepower supply device 10 matches the present total voltage of the battery30 or does not match, that is, is at higher voltage levels, or is atlower voltage levels. Optionally, the second instruction can be forenquiring whether it is suitable to use present output-voltage of thepower supply device 10 as the charging voltage, which is output by thepower supply device 10 in the second charging mode and used for chargingthe device to be charged. The reply instruction of the secondinstruction is for indicating whether the present output-voltage of thepower supply device 10 is suitable or unsuitable, that is, at highervoltage levels or at lower voltage levels. The present output-voltage ofthe power supply device 10 matching the present total voltage of thebattery 30, or the present output-voltage of the power supply device 10being suitable to be used as the charging voltage which is output by thepower supply device 10 in the second charging mode and used for chargingthe device to be charged can be understood as follows. The presentoutput-voltage of the power supply device 10 is slightly higher than thepresent total voltage of the battery, and the difference between theoutput-voltage of the power supply device 10 and the present totalvoltage of the battery is within a preset range (usually at a level ofseveral hundred millivolts (mV)).

Optionally, in some implementations, the communication circuit 23 canconduct two-way communication with the power supply device 10, so as tocontrol output of the power supply device 10 in the second charging modeas follows. The communication circuit 23 conducts two-way communicationwith the power supply device 10, so as to determine charging currentwhich is output by the power supply device 10 in the second chargingmode and used for charging the device to be charged.

Optionally, in some implementations, the communication circuit 23 canconduct two-way communication with the power supply device 10 todetermine charging current which is output by the power supply device 10in the second charging mode and used for charging the device to becharged as follows. The communication circuit 23 receives a thirdinstruction sent by the power supply device 10, the third instruction isfor enquiring a maximum charging current the device to be chargedsupports; the communication circuit 23 sends a reply instruction of thethird instruction to the power supply device 10, the reply instructionof the third instruction is for indicating the maximum charging currentthe device to be charged supports, so that the power supply device 10can determine the charging current which is output by the power supplydevice 10 in the second charging mode and used for charging the deviceto be charged, according to the maximum charging current the device tobe charged supports. It should be understood that, the communicationcircuit 23 determining the charging current which is output by the powersupply device 10 in the second charging mode and used for charging thedevice to be charged according to the maximum charging current thedevice to be charged supports can be implemented in various manners. Forexample, the power supply device 10 can determine the maximum chargingcurrent the device to be charged supports as the charging current whichis output by the power supply device 10 in the second charging mode andused for charging the device to be charged, or comprehensively take intoaccount the maximum charging current the device to be charged supportsand other factors such as current output capability of the power supplydevice 10 itself to determine the charging current which is output bythe power supply device 10 in the second charging mode and used forcharging the device to be charged.

Optionally, in some implementations, the communication circuit 23conducts two-way communication with the power supply device 10 tocontrol output of the power supply device 10 in the second charging modeas follows. The communication circuit 23 conducts two-way communicationwith the power supply device 10 to adjust output-current of the powersupply device 10 in the second charging mode.

Specifically, the communication circuit 23 conducts two-waycommunication with the power supply device 10 to adjust theoutput-current of the power supply device 10 as follows. Thecommunication circuit 23 receives a fourth instruction from the powersupply device 10, the fourth instruction is for enquiring present totalvoltage of the battery; the communication circuit 23 sends a replyinstruction of the fourth instruction to the power supply device 10, thereply instruction of the fourth instruction is for indicating thepresent total voltage of the battery, so that the power supply device 10can adjust the output-current of the power supply device 10 according tothe present total voltage of the battery.

Optionally, in some implementations, the communication circuit 23conducts two-way communication with the power supply device 10, so as tocontrol output of the power supply device 10 in the second charging modeas follows. The communication circuit 23 conducts two-way communicationwith the power supply device 10 to determine whether there is contactfailure in a charging interface.

Specifically, the communication circuit 23 can conduct two-waycommunication with the power supply device 10 to determine whether thereis contact failure in the charging interface as follows. Thecommunication circuit 23 receives a fourth instruction sent by the powersupply device 10, the fourth instruction is for enquiring presentvoltage of the battery of the device to be charged; the communicationcircuit 23 sends a reply instruction of the fourth instruction to thepower supply device 10, the reply instruction of the fourth instructionis for indicating the present voltage of the battery of the device to becharged, so that the power supply device 10 can determine whether thereis contact failure in the charging interface according to output voltageof the power supply 10 and the present voltage of the battery of thedevice to be charged. For instance, in case that the power supply device10 determines that difference between the output voltage of the powersupply 10 and the present voltage of the battery of the device to becharged is greater than a preset voltage threshold value, it indicatesthat impedance, which is obtained by the difference (that is, thedifference between the output voltage of the power supply 10 and thepresent voltage of the battery of the device to be charged) divided byoutput-current of the power supply device 10, is greater than a presetimpedance threshold value, it can be determined that there is contactfailure in the charging interface.

Optionally, in some implementations, contact failure in the charginginterface can be determined by the device to be charged. For example,the communication circuit 23 sends a sixth instruction to the powersupply device 10, the sixth instruction is for enquiring output-voltageof the power supply device 10; the communication circuit 23 receives areply instruction of the sixth instruction from the power supply device10, the reply instruction of the sixth instruction is for indicating theoutput-voltage of the power supply device 10, the communication circuit23 determines whether there is contact failure in the charging interfaceaccording to present voltage of the battery and the output-voltage ofthe power supply 10. When the communication circuit 23 determines thatthere is contact failure in the charging interface, the communicationcircuit 23 can send a fifth instruction to the power supply device 10,the fifth instruction is for indicating contact failure in the charginginterface. After receiving the fifth instruction, the power supplydevice 10 can exit the second charging mode.

The following will describe in detail a communication process betweenthe power supply device 10 and the device to be charged 40 (thecommunication circuit 23 of the device to be charged 40, to be specific)in conjunction with FIG. 13. It should be noted that, the example ofFIG. 13 is just for those skilled in the art to understand theimplementations of the disclosure, instead of limiting theimplementations of the disclosure to specific numeric values or specificsituations of the example. Those skilled in the art can make equivalentmodifications and changes without departing from the scope of theimplementations of the disclosure.

As illustrated in FIG. 13, the communication procedure between the powersupply device 10 and the device to be charged 40 (also referred to asthe communication procedure of a quick charging process) can include thefollowing five stages.

Stage 1:

After the device to be charged 40 is coupled with the power supplydevice 10, the device to be charged 40 can detect the type of the powersupply device 10 though data line D+ and data line D−. When the powersupply device 10 is detected to be a power supply device speciallyconfigured to charge such as an adaptor, current absorbed by the deviceto be charged 40 can be higher than a preset current threshold value I2(can be 1 A, for example). When the power supply device 10 detects thatoutput-current of the power supply device 10 is larger than or equal toI2 within a preset duration (can be a continuous time period T1, forexample), the power supply device 10 can consider that identification ofthe type of the power supply device by the device to be charged 40 iscompleted. Next, the power supply device 10 begins a negotiation processwith the device to be charged 40 and send Instruction 1 (correspondingto the first instruction mentioned above), so as to enquire whether thedevice to be charged 40 agrees to be charged by the power supply device10 in the second charging mode.

When the power supply device 10 receives a reply instruction ofInstruction 1 and the reply instruction of Instruction 1 indicates thatthe device to be charged 40 disagrees to be charged by the power supplydevice 10 in the second charging mode, the power supply device 10detects once again the output-current of the power supply device 10.When the output-current of the power supply device 10 is still largerthan or equal to I2 within a preset continuous duration (can be acontinuous time period T1), the power supply device 10 sends once againInstruction 1 to enquire whether the device to be charged 40 agrees tobe charged by the power supply device 10 in the second charging mode.The power supply device 10 repeats the above operations at Stage 1 untilthe device to be charged 40 agrees to be charged by the power supplydevice 10 in the second charging mode, or the output-current of thepower supply device 10 is no longer larger than or equal to I2.

When the device to be charged 40 agrees to be charged by the powersupply device 10 in the second charging mode, the communicationprocedure proceeds to Stage 2.

Stage 2:

The output voltage of the power supply device 10 can include multiplegrades. The power supply device 10 sends Instruction 2 (corresponding tothe second instruction mentioned above) to enquire whether the outputvoltage of the power supply device 10 (present output-voltage) matchespresent voltage of the battery 30 of the device to be charged 40.

The device to be charged 40 sends a reply instruction of Instruction 2to indicate whether the output voltage of the power supply device 10matches the present voltage of the battery 30 of the device to becharged 40 or does not match, that is, is at higher levels, or is atlower levels. When the reply instruction of Instruction 2 indicates thatthe output voltage of the power supply device 10 is at higher levels oris at lower levels, the power supply device 10 can adjust the outputvoltage of the power supply device 10 by one grade and send once againInstruction 2 to the device to be charged 40 to enquire whether theoutput voltage of the power supply device 10 matches the present voltageof the battery. Repeat the above operations until the device to becharged 40 determines that the output voltage of the power supply device10 matches the present voltage of the battery 30 of the device to becharged 40. and proceed to Stage 3.

Stage 3:

The power supply device 10 sends Instruction 3 (corresponding to thethird instruction mentioned above) to enquire a maximum charging currentthe device to be charged 40 supports. The device to be charged 40 sendsa reply instruction of Instruction 3 to indicate the maximum chargingcurrent the device to be charged 40 supports. Proceed to Stage 4.

Stage 4:

The power supply device 10 determines, according to the maximum chargingcurrent the device to be charged 40 supports, the charging current whichis output by the power supply device 10 in the second charging mode andused for charging the device to be charged 40. Proceed to Stage 5, theconstant-current charging stage.

Stage 5:

After proceeding to the constant-current charging stage, the powersupply device 10 can send Instruction 4 (corresponding to the fourthinstruction mentioned above) to the device to be charged 40 at certaintime intervals, so as to enquire present voltage of the battery 30 ofthe device to be charged 40. The device to be charged 40 can send areply instruction of Instruction 4 to feed back the present voltage ofthe battery. The power supply device 10 can determine whether thecharging interface is in a good contact and whether it is necessary toreduce the output current of the power supply device 10, according tothe present voltage of the battery. When the power supply device 10determines that there is contact failure in the charging interface, thepower supply device 10 can send Instruction 5 (corresponding to thefifth instruction mentioned above), thereby exiting the second chargingmode and being reset to return to Stage 1.

Optionally, in some implementations, at Stage 1, when the device to becharged 40 sends the reply instruction of Instruction 1, the replyinstruction of Instruction 1 can carry path impedance data (orinformation) of the device to be charged 40. The path impedance data ofthe device to be charged 40 can be used for determining whether thecharging interface is in a good contact at Stage 5.

Optionally, in some implementations, at Stage 2, duration from when thedevice to be charged 40 agrees to be charged by the power supply device10 in the second charging mode to when the power supply device 10adjusts the output voltage thereof to a suitable charging voltage can becontrolled within a certain range. When the duration is beyond thecertain range, the power supply device 10 or the device to be charged 40can determine that the communication process is abnormal, being reset toreturn to Stage 1.

Optionally, in some implementations, at Stage 2, when the output voltageof the power supply device 10 is higher than the present voltage of thebattery of the device to be charged 40 by ΔV(ΔV can be set between 200mV and 500 mV), the device to be charged 40 can send the replyinstruction of Instruction 2 to indicate that the output voltage of thepower supply device 10 matches the voltage of the battery of the deviceto be charged 40.

Optionally, in some implementations, at Stage 4, adjusting speed of theoutput current of the power supply device 10 can be controlled within acertain range, so as to avoid abnormality of the charging processresulting from excessively high adjusting speed.

Optionally, in some implementations, at Stage 5, change magnitude of theoutput current of the power supply device 10 can be controlled within5%.

Optionally, in some implementations, at Stage 5, the power supply device10 can detect in real time impedance of charging path. Specifically, thepower supply device 10 can detect the impedance of charging pathaccording to the output voltage and the output current of the powersupply device 10 and the present voltage of the battery fed back by thedevice to be charged 40. When the impedance of charging path is higherthan the impedance of path of the device to be charged 40 plus impedanceof a charging cable, it indicates that there is contact failure in thecharging interface, and thus the power supply device 10 stops chargingthe device to be charged 40 in the second charging mode.

Optionally, in some implementations, after the power supply device 10enables the second charging mode to charge the device to be charged 40,time intervals of communication between the power supply device 10 andthe device to be charged 40 can be controlled within a certain range, toavoid abnormality of communication resulting from excessively short timeintervals of communication.

Optionally, in some implementations, stopping of the charging process(or stopping of the power supply device 10 charging the device to becharged 40 in the second charging mode) can include a recoverablestopping and a non-recoverable stopping.

For example, when it is detected that the battery of the device to becharged 40 is fully charged or there is contact failure in the charginginterface, the charging process stops, a charging communication processis reset, and the charging process enters again Stage 1. Then, when thedevice to be charged 40 disagrees to be charged by the power supplydevice 10 in the second charging mode, the communication procedure willnot proceed to Stage 2. The stopping of the charging process in thiscase can be considered as the non-recoverable stopping.

For another example, when there is abnormality of the communicationbetween the power supply device 10 and the device to be charged 40, thecharging process stops, the charging communication process is reset, andthe charging process enters again Stage 1. After requirements on Stage 1are satisfied, the device to be charged 40 agrees to be charged by thepower supply device 10 in the second charging mode, so as to recover thecharging process. The stopping of the charging process in this case canbe considered as the recoverable stopping.

For yet another example, when the device to be charged 40 detectsabnormality of the battery, the charging process stops and is reset toenter again Stage 1. Then, the device to be charged 40 disagrees to becharged by the power supply device 10 in the second charging mode. Afterthe battery returns to normal and the requirements on Stage 1 aresatisfied, the device to be charged 40 agrees to be charged by the powersupply device in the second charging mode. The stopping of the quickcharging process in this case can be considered as the recoverablestopping.

The above communication steps or operations of FIG. 13 are justillustrative. For instance, at Stage 1, after the device to be charged40 is coupled with the power supply device 10, handshake communicationbetween the device to be charged 40 and the power supply device 10 canalso be initiated by the device to be charged 40. In other words, thedevice to be charged 40 sends Instruction 1, to enquire whether thepower supply device 10 enables the second charging mode. When the deviceto be charged 40 receives a reply instruction from the power supplydevice 10 indicating that the power supply device 10 agrees to chargethe device to be charged 40 in the second charging mode, the powersupply device 10 begins to charge the battery of the device to becharged 40 in the second charging mode.

For another instance, after Stage 5, the communication procedure canfurther include the constant-voltage charging stage. Specifically, atStage 5, the device to be charged 40 can feed back the present voltageof the battery to the power supply device 10. When the present voltageof the battery reaches a threshold value of charging voltage in theconstant-voltage charging stage, the charging stage turns to theconstant-voltage charging stage from the constant-current chargingstage. In the constant-voltage charging stage, the charging currentgradually decreases. When the charging current decreases to a certainthreshold value, it indicates that the battery of the device to becharged 40 is fully charged, and thus the whole charging process isstopped.

Apparatus implementations of the disclosure are described in detailabove in conjunction with FIG. 1 to FIG. 13. The following will describein detail method implementations of the disclosure in conjunction withFIG. 14. It should be understood that, description of method anddescription of apparatus correspond to each other. For simplicity,repeated description will be properly omitted.

FIG. 14 is a schematic flowchart illustrating a battery managementmethod according to an implementation of the present disclosure. Thebattery management method illustrated in FIG. 14 is applicable to abattery management circuit including a first charging channel, abalancing circuit, and a communication circuit. Through the firstcharging channel, charging voltage and/or charging current is receivedfrom a power supply device and applied directly to a battery forcharging. The battery includes a first cell and a second cell coupled inseries. The balancing circuit is coupled with the first cell and thesecond cell and configured to balance voltage of the first cell andvoltage of the second cell. The balancing circuit includes an RLC seriescircuit, a switch circuit, and a control circuit. The switch circuit hasone end coupled with the first cell and the second cell and another endcoupled with the RLC series circuit, and the switch circuit has acontrol end coupled with the control circuit.

The battery management method includes operations at blocks 1410 to1420. The following will describe the method in detail.

At block 1410, when the power supply device charges the battery throughthe first charging channel, the communication circuit communicates withthe power supply device to make magnitude of the charging voltage and/orcharging current received from the power supply device match a presentcharging stage of the battery.

At block 1420, when the voltage of the first cell and the voltage of thesecond cell are unbalanced, the control circuit controls the switchcircuit to make the first cell and the second cell alternately form aclosed loop with the RLC series circuit to provide input voltage for theRLC series circuit.

Optionally, in some implementations, the control circuit controls theswitch circuit to make frequency of input voltage of the RLC seriescircuit be equal to resonant frequency of the RLC series circuit.

Optionally, in some implementations, the switch circuit includes a firstswitch transistor, a second switch transistor, a third switchtransistor, and a fourth switch transistor. The first switch transistorhas a first connected end coupled with a positive electrode of the firstcell and a second connected end coupled with a first connected end ofthe second switch transistor. The second switch transistor has a secondconnected end coupled with a first connected end of the third switchtransistor and a negative electrode of the first cell. The third switchtransistor has a second connected end coupled with a first connected endof the fourth switch transistor. The fourth switch transistor has asecond connected end coupled with a negative electrode of the secondcell. The second cell has a positive electrode coupled with a negativeelectrode of the first cell. The first switch transistor, the secondswitch transistor, the third switch transistor, and the fourth switchtransistor each has a control end coupled with the control circuit.Components of the RLC series circuit are coupled in series between thesecond connected end of the first switch transistor and the secondconnected end of the third switch transistor.

Optionally, in some implementations, the switch circuit includes a firstswitch transistor, a second switch transistor, a third switchtransistor, and a fourth switch transistor. The first switch transistorhas a first connected end coupled with a positive electrode of the firstcell and a second connected end coupled with a first connected end ofthe second switch transistor. The second switch transistor has a secondconnected end coupled with a first connected end of the third switchtransistor. The third switch transistor having a second connected endcoupled with a first connected end of the fourth switch transistor. Thefourth switch transistor having a second connected end coupled with anegative electrode of the second cell. The second cell having a positiveelectrode coupled with a negative electrode of the first cell. The firstswitch transistor, the second switch transistor, the third switchtransistor, and the fourth switch transistor each has a control endcoupled with the control circuit. At least part of components of the RLCseries circuit are coupled in series between the second connected end ofthe second switch transistor and the negative electrode of the firstcell. Components of the RLC series circuit, other than the at least partof components of the RLC series circuit (that is, those coupled inseries between the second connected end of the second switch transistorand the negative electrode of the first cell) are coupled in seriesbetween the second connected end of the first switch transistor and thesecond connected end of the third switch transistor.

Optionally, in some implementations, when the voltage of the first celland the voltage of the second cell are unbalanced, operations at block1420 can include the following. When the voltage of the first cell andthe voltage of the second cell are unbalanced and the voltage of thefirst cell is higher than the voltage of the second cell, control thefirst switch transistor and the third switch transistor to an on-statefrom time t0 to time t1 and control the second switch transistor and thefourth switch transistor to an off-state from time t0 to time t1, wheretime t0 represents a start time of a work period of the control circuit;control the first switch transistor, the second switch transistor, thethird switch transistor, and the fourth switch transistor to theoff-state from time t1 to time t2, where a time period from time t1 totime t2 represents a preset first dead time; control the second switchtransistor and the fourth switch transistor to the on-state from time t2to time t3 and control the first switch transistor and the third switchtransistor to the off-state from time t2 to time t3; control the firstswitch transistor, the second switch transistor, the third switchtransistor, and the fourth switch transistor to the off-state from timet3 to time t4, where t4 represents an end time of the work period and atime period from time t3 to time t4 represents a preset second deadtime.

Optionally, in some implementations, working frequency of the controlcircuit is equal to the resonant frequency of the RLC series circuit.

Optionally, in some implementations, when the voltage of the first celland the voltage of the second cell are unbalanced, operations at block1420 can include the following. When the voltage of the first cell andthe voltage of the second cell are unbalanced and the voltage of thesecond cell is higher than the voltage of the first cell, control thesecond switch transistor and the fourth switch transistor to an on-statefrom time t0 to time t1 and control the first switch transistor and thethird switch transistor to an off-state from time t0 to time t1, wheretime t0 represents a start time of a work period of the control circuit;control the first switch transistor, the second switch transistor, thethird switch transistor, and the fourth switch transistor to theoff-state from time t1 to time t2, where a time period from time t1 totime t2 represents a preset first dead time; control the first switchtransistor and the third switch transistor to the on-state from time t2to time t3 and control the second switch transistor and the fourthswitch transistor to the off-state from time t2 to time t3; control thefirst switch transistor, the second switch transistor, the third switchtransistor, and the fourth switch transistor to the off-state from timet3 to time t4, where time t4 represents an end time of the work period,and a time period from time t3 to time t4 represents a second dead time.

Optionally, in some implementations, working frequency of the controlcircuit is equal to the resonant frequency of the RLC series circuit.

Optionally, in some implementations, the battery management circuitfurther includes a second charging channel provided with a boostcircuit, the boost circuit is configured to receive initial voltage fromthe power supply device and increase the initial voltage to a targetvoltage to charge the battery according to the target voltage, when thepower supply device charges the battery through the second chargingchannel. The initial voltage is lower than total voltage of the batteryand the target voltage is higher than the total voltage of the battery.

The above example illustrates the balancing circuit 22, as a part of thebattery management circuit 20, providing a balancing method to balancethe voltage of the first cell 31 a and the voltage of the second cell 31b, where the first cell 31 a and the second cell 31 b are coupled inseries and managed by the battery management circuit 20. However,implementations of the disclosure are not limited to the above example.Practically, the balancing circuit 22 can be applied to any situationwhere voltage between cells needs to be balanced.

Those of ordinary skill in the art will appreciate that units (includingsub-units) and algorithmic operations of various examples described inconnection with implementations herein can be implemented by electronichardware or by a combination of computer software and electronichardware. Whether these functions are performed by means of hardware orsoftware depends on the application and the design constraints of theassociated technical solution. A professional technician may usedifferent methods with regard to each particular application toimplement the described functionality, but such methods should not beregarded as lying beyond the scope of the disclosure.

It will be evident to those skilled in the art that the correspondingprocesses of the above method implementations can be referred to for theworking processes of the foregoing systems, apparatuses, and units, forpurposes of convenience and simplicity and will not be repeated herein.

It will be appreciated that the systems, apparatuses, and methodsdisclosed in implementations herein may also be implemented in variousother manners. For example, the above apparatus implementations aremerely illustrative, e.g., the division of units (including sub-units)is only a division of logical functions, and there may exist other waysof division in practice, e.g., multiple units (including sub-units) orcomponents may be combined or may be integrated into another system, orsome features may be ignored or not included. In other respects, thecoupling or direct coupling or communication connection as illustratedor discussed may be an indirect coupling or communication connectionthrough some interface, device or unit, and may be electrical,mechanical, or otherwise.

Separated units (including sub-units) as illustrated may or may not bephysically separated. Components or parts displayed as units (includingsub-units) may or may not be physical units, and may reside at onelocation or may be distributed to multiple networked units. Some or allof the units (including sub-units) may be selectively adopted accordingto practical needs to achieve desired objectives of the disclosure.

Additionally, various functional units (including sub-units) describedin implementations herein may be integrated into one processing unit ormay be present as a number of physically separated units, and two ormore units may be integrated into one.

If the integrated units are implemented as software functional units andsold or used as standalone products, they may be stored in a computerreadable storage medium. Based on such an understanding, the essentialtechnical solution, or the portion that contributes to the prior art, orall or part of the technical solution of the disclosure may be embodiedas software products. Computer software products can be stored in astorage medium and may include multiple instructions that, whenexecuted, can cause a computing device, e.g., a personal computer, aserver, a second adapter, a network device, etc., to execute some or alloperations of the methods as described in the various implementations.The above storage medium may include various kinds of media that canstore program code, such as a USB flash disk, a mobile hard drive, aread-only memory (ROM), a random access memory (RAM), a magnetic disk,or an optical disk.

What is claimed is:
 1. A battery management circuit, comprising: a firstcharging channel, a balancing circuit, and a communication circuit,wherein at least one of charging voltage and charging current isreceived from a power supply device and applied directly to a batteryfor charging through the first charging channel, the battery comprisinga first cell and a second cell coupled in series; the communicationcircuit is configured to communicate with the power supply device tomake magnitude of at least one of the charging voltage and the chargingcurrent received from the power supply device match a present chargingstage of the battery, when the power supply device charges the batterythrough the first charging channel; the balancing circuit is coupledwith the first cell and the second cell and configured to balance avoltage of the first cell and a voltage of the second cell; thebalancing circuit comprises an RLC series circuit, a switch circuit, anda control circuit; the switch circuit has one end coupled with the firstcell and the second cell and another end coupled with the RLC seriescircuit, and the switch circuit having a control end coupled with thecontrol circuit; and the control circuit is configured to control theswitch circuit to make the first cell and the second cell alternatelyform a closed loop with the RLC series circuit to provide input voltagefor the RLC series circuit, when the voltage of the first cell and thevoltage of the second cell are unbalanced.
 2. The battery managementcircuit of claim 1, wherein the control circuit is further configured tocontrol the switch circuit to make frequency of input voltage of the RLCseries circuit be equal to resonant frequency of the RLC series circuit.3. The battery management circuit of claim 1, wherein the switch circuitcomprises a first switch transistor, a second switch transistor, a thirdswitch transistor, and a fourth switch transistor, the first switchtransistor having a first connected end coupled with a positiveelectrode of the first cell and a second connected end coupled with afirst connected end of the second switch transistor, the second switchtransistor having a second connected end coupled with a first connectedend of the third switch transistor, the third switch transistor having asecond connected end coupled with a first connected end of the fourthswitch transistor, the fourth switch transistor having a secondconnected end coupled with a negative electrode of the second cell, thesecond cell having a positive electrode coupled with a negativeelectrode of the first cell, and the first switch transistor, the secondswitch transistor, the third switch transistor, and the fourth switchtransistor each having a control end coupled with the control circuit.4. The battery management circuit of claim 3, wherein the secondconnected end of the second switch transistor is further coupled withthe negative electrode of the first cell, and components of the RLCseries circuit is coupled in series between the second connected end ofthe first switch transistor and the second connected end of the thirdswitch transistor.
 5. The battery management circuit of claim 3, whereinat least part of components of the RLC series circuit are coupled inseries between the second connected end of the second switch transistorand the negative electrode of the first cell, and components of the RLCseries circuit, other than those coupled in series between the secondconnected end of the second switch transistor and the negative electrodeof the first cell, are coupled in series between the second connectedend of the first switch transistor and the second connected end of thethird switch transistor.
 6. The battery management circuit of claim 3,wherein the voltage of the first cell and the voltage of the second cellare unbalanced and the voltage of the first cell is higher than thevoltage of the second cell, and the control circuit is furtherconfigured to: control the first switch transistor and the third switchtransistor to an on-state from time t0 to time t1 and control the secondswitch transistor and the fourth switch transistor to an off-state fromtime t0 to time t1, time t0 representing a start time of a work periodof the control circuit; control the first switch transistor, the secondswitch transistor, the third switch transistor, and the fourth switchtransistor to the off-state from time t1 to time t2, and a time periodfrom time t1 to time t2 representing a preset first dead time; controlthe second switch transistor and the fourth switch transistor to theon-state from time t2 to time t3 and control the first switch transistorand the third switch transistor to the off-state from time t2 to timet3; and control the first switch transistor, the second switchtransistor, the third switch transistor, and the fourth switchtransistor to the off-state from time t3 to time t4, time t4representing an end time of the work period, and a time period from timet3 to time t4 representing a preset second dead time.
 7. The batterymanagement circuit of claim 3, wherein the voltage of the first cell andthe voltage of the second cell are unbalanced and the voltage of thesecond cell is higher than the voltage of the first cell, and thecontrol circuit is further configured to: control the second switchtransistor and the fourth switch transistor to an on-state from time t0to time t1 and control the first switch transistor and the third switchtransistor to an off-state from time t0 to time t1, time t0 representinga start time of a work period of the control circuit; control the firstswitch transistor, the second switch transistor, the third switchtransistor, and the fourth switch transistor to the off-state from timet1 to time t2, a time period from time t1 to time t2 representing apreset first dead time; control the first switch transistor and thethird switch transistor to the on-state from time the t2 to time t3 andcontrol the second switch transistor and the fourth switch transistor tothe off-state from time t2 to time t3; and control the first switchtransistor, the second switch transistor, the third switch transistor,and the fourth switch transistor in the off-state from time t3 to timet4, time t4 representing an end time of the work period, and a timeperiod from time t3 to time t4 representing a second dead time.
 8. Thebattery management circuit of claim 1, further comprising a secondcharging channel provided with a boost circuit, wherein the boostcircuit is configured to receive initial voltage from the power supplydevice and increase the initial voltage to a target voltage to chargethe battery according to the target voltage, when the power supplydevice charges the battery through the second charging channel, whereinthe initial voltage is lower than total voltage of the battery and thetarget voltage is higher than the total voltage of the battery.
 9. Adevice to be charged, comprising: a battery, comprising a first cell anda second cell coupled in series; a first charging channel, through whichat least one of charging voltage and charging current are received froma power supply device and applied directly to the battery for charging;a communication circuit, being configured to communicate with the powersupply device to make magnitude of at least one of the charging voltageand the charging current received from the power supply device match apresent charging stage of the battery, when the power supply devicecharges the battery through the first charging channel; and a balancingcircuit, coupled with the first cell and the second cell and configuredto balance a voltage of the first cell and a voltage of the second cell,the balancing circuit comprising an RLC series circuit, a switchcircuit, and a control circuit, the switch circuit having one endcoupled with the first cell and the second cell and another end coupledwith the RLC series circuit, and the switch circuit having a control endcoupled with the control circuit; and the control circuit beingconfigured to control the switch circuit to make the first cell and thesecond cell alternately form a closed loop with the RLC series circuitto provide input voltage for the RLC series circuit, when the voltage ofthe first cell and the voltage of the second cell are unbalanced. 10.The device of claim 9, wherein the control circuit is further configuredto control the switch circuit to make frequency of input voltage of theRLC series circuit be equal to resonant frequency of the RLC seriescircuit.
 11. The device of claim 9, wherein the switch circuit comprisesa first switch transistor, a second switch transistor, a third switchtransistor, and a fourth switch transistor, the first switch transistorhaving a first connected end coupled with a positive electrode of thefirst cell and a second connected end coupled with a first connected endof the second switch transistor, the second switch transistor having asecond connected end coupled with a first connected end of the thirdswitch transistor, the third switch transistor having a second connectedend coupled with a first connected end of the fourth switch transistor,the fourth switch transistor having a second connected end coupled witha negative electrode of the second cell; the second cell comprises apositive electrode coupled with a negative electrode of the first cell,and the first switch transistor, the second switch transistor, the thirdswitch transistor, and the fourth switch transistor each having acontrol end coupled with the control circuit.
 12. The device of claim11, wherein the second connected end of the second switch transistor isfurther coupled with the negative electrode of the first cell, andcomponents of the RLC series circuit are coupled in series between thesecond connected end of the first switch transistor and the secondconnected end of the third switch transistor.
 13. The device of claim11, wherein at least part of components of the RLC series circuit arecoupled in series between the second connected end of the second switchtransistor and the negative electrode of the first cell, and componentsof the RLC series circuit, other than those coupled in series betweenthe second connected end of the second switch transistor and thenegative electrode of the first cell, are coupled in series between thesecond connected end of the first switch transistor and the secondconnected end of the third switch transistor.
 14. The device of claim11, wherein the voltage of the first cell and the voltage of the secondcell are unbalanced and the voltage of the first cell is higher than thevoltage of the second cell, and the control circuit is furtherconfigured to: control the first switch transistor and the third switchtransistor to an on-state from time t0 to time t1 and control the secondswitch transistor and the fourth switch transistor to an off-state fromtime t0 to time t1, time t0 representing a start time of a work periodof the control circuit; control the first switch transistor, the secondswitch transistor, the third switch transistor, and the fourth switchtransistor to the off-state from time t1 to time t2, and a time periodfrom time t1 to time t2 representing a preset first dead time; controlthe second switch transistor and the fourth switch transistor to theon-state from time t2 to time t3 and control the first switch transistorand the third switch transistor to the off-state from time t2 to timet3; and control the first switch transistor, the second switchtransistor, the third switch transistor, and the fourth switchtransistor to the off-state from time t3 to time t4, time t4representing an end time of the work period, and a time period from timet3 to time t4 representing a preset second dead time.
 15. The device ofclaim 11, wherein the voltage of the first cell and the voltage of thesecond cell are unbalanced and the voltage of the second cell is higherthan the voltage of the first cell, and the control circuit is furtherconfigured to: control the second switch transistor and the fourthswitch transistor to an on-state from time t0 to time t1 and control thefirst switch transistor and the third switch transistor to an off-statefrom time t0 to time t1, time t0 representing a start time of a workperiod of the control circuit; control the first switch transistor, thesecond switch transistor, the third switch transistor, and the fourthswitch transistor to the off-state from time t1 to time t2, a timeperiod from time t1 to time t2 representing a preset first dead time;control the first switch transistor and the third switch transistor tothe on-state from time the t2 to time t3 and control the second switchtransistor and the fourth switch transistor to the off-state from timet2 to time t3; and control the first switch transistor, the secondswitch transistor, the third switch transistor, and the fourth switchtransistor in the off-state from time t3 to time t4, time t4representing an end time of the work period, and a time period from timet3 to time t4 representing a second dead time.
 16. A balancing circuit,comprising: an RLC series circuit, a switch circuit, and a controlcircuit, wherein the switch circuit has one end coupled with a firstcell and a second cell and another end coupled with the RLC seriescircuit, and the switch circuit has a control end coupled with thecontrol circuit; and the control circuit is configured to control theswitch circuit to make the first cell and the second cell alternatelyform a closed loop with the RLC series circuit to provide input voltagefor the RLC series circuit, when a voltage of the first cell and avoltage of the second cell are unbalanced.
 17. The balancing circuit ofclaim 16, wherein the control circuit is further configured to controlthe switch circuit to make frequency of input voltage of the RLC seriescircuit be equal to resonant frequency of the RLC series circuit. 18.The balancing circuit of claim 16, wherein the switch circuit comprisesa first switch transistor, a second switch transistor, a third switchtransistor, and a fourth switch transistor, the first switch transistorhaving a first connected end coupled with a positive electrode of thefirst cell and a second connected end coupled with a first connected endof the second switch transistor, the second switch transistor having asecond connected end coupled with a first connected end of the thirdswitch transistor, the third switch transistor having a second connectedend coupled with a first connected end of the fourth switch transistor,the fourth switch transistor having a second connected end coupled witha negative electrode of the second cell, the second cell having apositive electrode coupled with a negative electrode of the first cell,and the first switch transistor, the second switch transistor, the thirdswitch transistor, and the fourth switch transistor each having acontrol end coupled with the control circuit.
 19. The balancing circuitof claim 18, wherein the second connected end of the second switchtransistor is further coupled with the negative electrode of the firstcell, and components of the RLC series circuit are coupled in seriesbetween the second connected end of the first switch transistor and thesecond connected end of the third switch transistor.
 20. The balancingcircuit of claim 18, wherein at least part of components of the RLCseries circuit are coupled in series between the second connected end ofthe second switch transistor and the negative electrode of the firstcell, and components of the RLC series circuit, other than those coupledin series between the second connected end of the second switchtransistor and the negative electrode of the first cell, are coupled inseries between the second connected end of the first switch transistorand the second connected end of the third switch transistor.